Abstract Low back pain is the second most common reason for a visit to a physician, with direct medical costs exceeding $90 billion per year in the United States alone. These costs are driven primarily by 7-10% of patients who develop a chronic pain disorder that can last for many years. Fear of movement (i.e., kinesiophobia) due to expectations of pain and harm is an important risk indicator for the development of persistent pain and disability, with studies consistently showing that high fear is one of the strongest predictors of the transition to chronic low back pain (CLBP). Specifically, fear encourages the adoption of maladaptive movement patterns wherein tasks of daily living are performed with reduced lumbar spine flexion and compensatory increases of knee, hip, and arm shoulder flexion. While avoidance of lumbar flexion may benefit these back pain sufferers in the short-term by reducing their fear of injury, in the long-term limited lumbar flexion becomes an entrenched pattern that can lead to shortening of spinal peri-articular connective tissues, changes in surrounding muscles, and increased risk for chronicity. With the support of an NIH R21, we recently completed a Phase I trial of an immersive virtual reality dodgeball game designed specifically to increase lumbar flexion among individuals with CLBP and high fear of movement. The results of this proof-of-concept study demonstrated that 3 daily sessions of virtual dodgeball was safe, did not exacerbate existing back pain, was highly rated by participants, and increased lumbar spine flexion during gameplay. We now propose a Phase II RCT to determine the efficacy of a 9?week course of treatment of virtual dodgeball to reduce pain and disability. CLBP participants will be randomly assigned to play one of two versions of our virtual reality game. In the experimental group, gameplay will promote progressive increases in lumbar flexion. The control group will play the same immersive video game, but the parameters of the game will be modified such that only small excursions of lumbar flexion are needed to successfully complete gameplay. The co-primary clinical outcomes of changes in pain and disability will be assessed at 1-, 6-, 12-, 24-, and 48-weeks post-treatment. Additionally, individual differences in expected pain, expected harm, and lumbar flexion will be measured at pre-treatment baseline and at each of the follow-up intervals in the laboratory. Finally, participant activity in their natural environment will be monitored for 7 days following each follow-up laboratory visit. We have developed an innovative immersive video game that safely reduces expectations of pain/harm and increases lumbar flexion among individuals with CLBP. The proposed Phase II trial will have a significant impact on public health by testing the ability of this unique intervention to motivate CLBP sufferers to re-engage in the specific spinal motions necessary to promote recovery and to maintain these treatment gains.